Kenworth VIN Decoder: 11 Codes, and Most Are Not American

Type “Kenworth VIN decoder” into a search box and you get a page of input fields, most of them arranged to imply that a heavy truck needs a reader built specially for it. It does not. The number stamped on a sleeper tractor is built to the same federal standard as the number on a hatchback, and the register that turns the first three characters into a manufacturer is the same register for both. There is one system, it is public, and it reads this make on exactly the terms it reads every other.

What is worth reading is what that register actually records under the name. This page was written on 5 September 2026 and works from the archived read of NHTSA’s vPIC data behind it: 11 codes, 2 registered company names, 2 vehicle types, and a country column that is the most interesting thing on the page. Nothing here comes from a manufacturer briefing or from anyone’s recollection. It is the public filing, read line by line, with the gaps named where they fall rather than filled in.

The gaps are the reason a page like this is worth writing. The questions a buyer may bring to it — how this one was specified, what it has been doing for the miles already on it, whether the body on the back was ever inspected by anybody, whether the outstanding recall letter was acted on — are questions the seventeen characters were never designed to answer. Saying that plainly at the top is more useful than another input box.

One register reads every VIN, this make included

The vehicle identification number is a federal standard, and its structure does not change with the size or weight of the vehicle. Positions one to three are the world manufacturer identifier, assigned to the legal entity that builds and certifies the vehicle. Positions four to eight describe the vehicle in a scheme each manufacturer designs for itself. Position nine is a check digit computed arithmetically from the other sixteen characters. Position ten carries the model year. Position eleven identifies the assembling plant. The last six are the serial number.

That layout is identical on a day cab and on a saloon, which is why a general decoder handles this make as readily as anything else, and why the phrase “Kenworth VIN decoder” describes a search habit rather than a separate piece of software. Our guide to reading a VIN position by position sets out the whole layout, and the by-make index collects what the register holds for every manufacturer we have read.

Where a make-specific decoder would genuinely earn its keep is the middle block, and here we have to be straight about a limit. Positions four to eight are the manufacturer’s own descriptor scheme, and the federal register does not publish the key to it. The register records who holds each prefix, what class of vehicle the prefix covers, which country the entity is recorded against and when the code was opened. It does not record that a particular character in position six means one cab configuration on one product line and something else on another.

So this page prints no position-by-position table for the make, and you should treat the ones that circulate with suspicion. None of them is the register, and there is no way for a reader to check where their contents came from. Decoding a real number returns the descriptor fields as the federal system resolves them for that specific vehicle, which is a different and far more dependable thing than a printed key assembled from a forum thread.

What a decode returns in that block depends on which fields the manufacturer submitted for the vehicle. Our page on looking up a commercial truck by VIN covers the fields a commercial decode can return and why the engine manufacturer field is worth reading first.

The 11 codes, printed in full

A VIN opens with three characters the manufacturer does not choose for itself. They are assigned centrally, published in full, and they identify the entity that filed for the right to issue numbers. Under this name there are 11 of them, and the whole set is short enough to put on the page.

Filed as Truck: 1XK, recorded against the United States; 2XK, against Canada; 3WK, against Mexico; SFN, against the United Kingdom; 3WM, against Mexico; 3XK, against Mexico; and 3NM, which carries no country at all.

Filed as Incomplete Vehicle: 1NK, recorded against the United States; 2NK, against Canada; 3BK, against Mexico; and 3NK, against Mexico.

That is the entire register entry. Not a selection, not the ones we thought worth mentioning — all 11, with nothing held back and nothing else to find. A count published elsewhere that differs from this one is either working from a different read of the register or counting something other than this make’s own registrations.

Two company names hold the set between them. KENWORTH TRUCK COMPANY holds 7 of the codes: 1XK, 2XK, 3WK, SFN, 1NK, 2NK and 3BK. KENWORTH MEXICANA SA DE CV holds the other 4: 3WM, 3NM, 3XK and 3NK. When a decode returns a company name you were not expecting, that split is one thing that can be behind it, and it is not an error in the lookup. The lookup is telling you which registered entity issued that number, which is the legally meaningful answer to a narrower question than most people think they are asking.

Where the codes are registered, and why that is the story here

Sort the 11 codes by the country recorded against them and the entry stops looking like a domestic truck maker’s file. Mexico carries 5. The United States carries 2. Canada carries 2. The United Kingdom carries 1. And 1 code has nothing in the column at all.

Nine of the 11 codes, in other words, are not recorded against the United States: eight name another country and one names none. It is worth being extremely precise about what that does and does not mean, because this is the single easiest thing on the page to misread.

The country field records where the registering entity filed. That is all it records. It is not a promise about where any particular truck was assembled, it is not a claim about a plant, and it does not tell you which market a given vehicle was built for. A code filed by an entity registered in one country can carry numbers issued on vehicles built elsewhere, and the register holds nothing that would let anyone tighten that up. Read the country line in a decode result as a fact about a filing and it stops being confusing.

The practical consequence is narrow and useful. If you decode a number on a truck and the result names a country you were not expecting, the sensible first assumption is that the register is right and your expectation was wrong. A code that appears in the public register is a code that was properly assigned. An unfamiliar prefix is not, by itself, evidence of anything wrong with the vehicle in front of you.

The United Kingdom entry is the one most likely to look out of place. SFN sits in the file alongside the North American codes, filed under the same company name as most of them, and there is nothing irregular about it. Across all 36 makes in our archived read of the register, only five have any code recorded against the United Kingdom, so it is an uncommon row to meet rather than a doubtful one.

The code that records no country at all

One row in this entry is worth its own section because it is the kind of thing that makes a careful reader distrust a whole dataset when it is not explained.

3NM is filed under KENWORTH MEXICANA SA DE CV as a Truck, registered on the same day as 3WM. Its country field is empty. Not “unknown”, not a placeholder — the field simply carries nothing. It is the only one of the 11 codes with an empty country field: the other 10 all carry one. The make’s country list names 4 countries against 11 codes because it lists the distinct countries that appear rather than one entry per code, and those 10 codes fall between the United States, Canada, Mexico and the United Kingdom.

This is not unique to the make. Across the 36 makes in the file, 13 have at least one code with no country recorded against it, so an empty country is an ordinary feature of the register rather than a sign that this particular entry has been mangled. What it means in practice is that for that one code, the register offers no country-of-filing answer at all, and no honest page can supply one.

We are not going to guess. It would be easy, and it would look plausible, to note that 3NM begins with the same character as the Mexican codes and is held by the same company as three of them, and then to write “so it is a Mexican registration”. The register does not say that, and the whole value of a page like this is that it prints what the register says. The honest answer to “which country is 3NM filed against?” is that the field is blank.

If your decode of a real number returns nothing in the country field, that is what has happened. It is not a fault in the decoder, and it should not be read as a hint that the vehicle came from somewhere unusual. It is a blank field in a public filing, faithfully reported.

1, 2, 3 and S: what the first character does here

Read the 11 codes as a list and a pattern falls out of them. The two codes recorded against the United States are 1XK and 1NK. The two recorded against Canada are 2XK and 2NK. Five of the six beginning with 3 — 3WK, 3WM, 3XK, 3BK and 3NK — are recorded against Mexico. The single code recorded against the United Kingdom is SFN. And 3NM, which begins with 3 like the Mexican codes, records nothing.

So across this entry, the leading character tracks the country of registration on every code that has one. That is a genuinely useful observation and a narrow one. It tells you which entity issued the number and, on this make, which country that entity is recorded against. It is not a trim distinction, not a specification difference, and not a signal that one truck is the proper version and another something lesser.

Keep the same caution attached to it that applies to the country column itself. The first character follows the filing, and the filing is not the plant. Position eleven of an individual number is the plant character, but the register does not publish the key that turns a plant character into a plant name, so this page prints no plant-code list. Anyone who does print one is working from something other than the federal data.

Two trucks wearing the same badge can therefore open with different characters, and that is ordinary. What would be worth investigating is not a leading character you did not expect, but a number that fails its own check digit, or a number on the vehicle that does not match the number on the paperwork.

4 of the 11 codes leave the factory unfinished

The vehicle-type column holds the second finding, and it changes what a decode is worth on a large share of the vehicles carrying this name.

Of the 11 codes, 7 are filed as Truck and 4 are filed as Incomplete Vehicle. There is no third type in the set. An incomplete vehicle, in the federal scheme, is exactly what the phrase says: a vehicle that leaves its manufacturer without its final body, sold on to another company to be finished. On a heavy vehicle that generally means a chassis and a cab — frame rails, running gear, driveline, cab and controls — with nothing at all behind the cab.

Three of those four codes are held by KENWORTH TRUCK COMPANY and one by KENWORTH MEXICANA SA DE CV, so the chassis registrations are not confined to a single entity or a single country of filing. 1NK is recorded against the United States, 2NK against Canada, and 3BK and 3NK against Mexico.

The company that finishes such a vehicle is a manufacturer in its own right as far as the regulations are concerned. It builds the mixer drum, the tank, the wrecker body, the crane, the box, the lift or whatever else the vehicle exists to do, and it certifies its own stage of the work. That is how an enormous range of vehicles that share almost nothing visually can all decode to the same chassis maker.

The consequence for a buyer is blunt. Decode the number on a mixer built on one of these chassis and the answer names this make. Decode the number on a bucket truck, a car carrier or a refuse body built on one, and the answer still names this make. In each case the decode is answering for the part the chassis maker built and certified, and it is silent about the part that determines what the vehicle is for, what it is worth and how well it was put together.

That is not a flaw in the decode. It is the decode doing precisely what it was designed to do, applied to a vehicle two companies built. The error belongs to the reader who takes the chassis maker’s name as a description of the whole machine.

The vehicle-type column is worth reading for what it leaves out as well. Every one of the 11 codes is filed as either Truck or Incomplete Vehicle. There is no passenger car class in this file, no multipurpose passenger vehicle class, no bus, no trailer. Whatever else the register knows about the make, it knows it as a maker of trucks and of chassis for other people to finish.

A bare chassis means a second plate to find

The practical answer follows straight from the incomplete-vehicle finding. On a vehicle that somebody else finished, there are two records to look for, and the decode only ever hands you one of them.

One of them is the chassis maker’s certification label. On a completed vehicle you should also expect a label from the company that finished it, applied when that company certified its own stage of the build. Find it, photograph it, and write down every identifier printed on it along with the company name. That name is what you search for when you want service documentation, parts availability, the weight ratings that apply to the finished vehicle, and any campaigns filed against the body rather than against the chassis.

The two labels are often near each other — the driver’s door aperture and the structure around it are the conventional places — but on bodied and converted vehicles the second one may be in the cab, inside a locker, or on the frame instead. Look for longer than you would on a car. Our guide to where the VIN is on a vehicle covers the standard locations, and on a bodied truck the standard locations are the beginning of the search rather than the end. A finished vehicle carrying no second label at all is a question worth asking out loud before money moves.

Recalls follow the same two-company logic, and this is where the gap costs real money. The federal recall lookup answers for the number you type into it, so a campaign filed by the chassis maker against that chassis will come back. A campaign filed by the finishing company against its own work may sit under a separate record entirely, and decoding the chassis number and stopping will not find it. Run the free check described in our guide to checking a vehicle for open recalls, then go and ask the body builder separately.

The weight rating deserves the same care. What a finished vehicle is rated to carry is a property of the finished vehicle, and the plate that governs it is not necessarily the chassis maker’s. Our page on GVWR by VIN explains where the rating is published and why it sometimes arrives as a range rather than as a single figure.

Two company names, and what a decode is actually telling you

The entry is filed between KENWORTH TRUCK COMPANY, which holds 7 codes, and KENWORTH MEXICANA SA DE CV, which holds 4. Both names contain the badge, which makes this entry easier to read than some: the registered entity is a legal fact and the badge is a marketing one, and there is no rule saying the two must match.

Even so, the distinction matters. A decode reports the registered entity that issued the number, character for character as filed. It does not tell you who designed the vehicle, who sells it, whose warranty applies, or whose name is on the dealership. Those are different facts held in different places, and the register is not the place.

The register also declines to explain the relationship between the two names. It gives each one a set of codes, a vehicle type against each code, a country where one was recorded, and a registration date. It does not say how the two companies relate to each other, why either was established, or which one is responsible for what. This site does not fill in that kind of blank from memory, so the two names are reported and left there.

One more thing follows from the split. The entity holding a code and the type filed against it do not line up neatly. KENWORTH TRUCK COMPANY holds 4 codes filed as Truck and 3 filed as Incomplete Vehicle. KENWORTH MEXICANA SA DE CV holds 3 filed as Truck and 1 filed as Incomplete Vehicle. A single registered company can hold several codes under the same type, and the register records no reason for any of it. It carries the code, the holder, the type, the country where there is one, and the date. No explanations are attached to any of those fields.

The registration dates, and what they are not

Every code in the register carries a date recording when it was registered. Read this entry’s dates in order and a simple pattern appears: 7 codes were registered on a single day in May 2015, 2 more on a day in March 2017, and the last 2 in October 2018, four days apart.

The split follows the two company names exactly. Every one of the 7 codes held by KENWORTH TRUCK COMPANY carries the same May 2015 date, and every one of the 4 held by KENWORTH MEXICANA SA DE CV was registered later. That is a fact about the file, cleanly observable, and it is the whole of what the dates support.

Now the caution, which matters more here than the observation. A registration date is the date a code was entered in the register. It is not the date any vehicle was built, not the date one was sold, not the date one was first titled, and emphatically not a model year. Codes can be registered ahead of use and can sit unused. A whole block of codes sharing one date is usually telling you something about when a register was populated rather than anything about vehicles.

The date that actually belongs to a vehicle sits at position ten of its own number, and our model-year chart explains how to read it. If you want to know how old the truck in front of you is, that is where to look, along with the paperwork. The dates in this section rank filings and stop there.

44 models, and why this page names none of them

The federal register holds 44 models for the make. That is the decoder’s vocabulary here — the set of names a decode can return when it resolves a specific number to this manufacturer.

Two things need saying about that count. The first is that it covers everything the register holds for the make across all years, not a current line-up and not a used-truck catalogue. The second is that the archived read behind this page carries the count and not the roster, so no model names are printed on this page.

That is a smaller point than it sounds and a more important one than it looks. Every make page on this site works from one archived read of the register, and the rule is that we publish what the read contains. Reciting model names from memory would be indistinguishable, to a reader, from reporting the data — and it would be indistinguishable, to a reader, from reporting the data. Where we hold the roster we print it. Here we hold the count, so the count is what you get.

The count is not the useful part anyway. What a buyer needs is the model returned for one specific vehicle, and that comes from decoding that vehicle’s number rather than from any list. You also cannot work backwards from a prefix to a model, because the register does not publish that relationship at all.

And a model name, however it arrives, is not a specification. The register knows the model line. It does not know the axle arrangement, the wheelbase, the engine, the gearbox, the ratio, the suspension, the fifth wheel or the sleeper configuration, and those are distinctions to establish from the vehicle and its paperwork instead.

A clean entry, with nothing to subtract

The register’s name endpoint matches company names as text rather than resolving brands, which means asking it for a common word drags in every small builder, trailer shop and specialist converter whose registered name happens to contain that string. Readers of a raw result can easily conclude that a marque holds a dozen codes it has nothing to do with, and how that noise is filtered is one reason published code counts disagree.

Querying the register for this name returns 0 unrelated matches. Nothing else on the register is filed under a name that catches the same string, so the entry a reader gets is the entry the company actually holds. Eleven codes, no strangers attached, nothing to filter by hand.

The make also registers under its own name rather than sitting beneath a parent group in the register. That is not true of every badge — several well-known names hold no codes at all in their own right, and their numbers are issued under a parent’s filing, which is why a register search on those badge names returns almost nothing useful. Here the badge and the register entry line up, and a reader who runs the same query will see the same 11 rows.

What the decode will not tell a buyer

This is the section that does the most work, because it is where the gap between what people expect from a VIN and what a VIN actually carries is widest.

The number is a build identity. It exists so a regulator can tie a recall campaign to a batch of vehicles, an insurer can tie a policy to an object, and a state can tie a title to that same object. It was never designed to describe the condition of a vehicle today, and it has no field for any of the following.

Service history. Nothing about oil changes, valve adjustments, injector work, clutch replacements, brake overhauls or the last time anybody looked at the driveline reaches the register, and none of it is encoded in the number. There may be no central record of it anywhere — only the folder the seller can or cannot produce, which is worth asking for and worth reading properly when it appears.

Whether a recall was actually completed. The federal recall lookup will tell you whether a campaign is recorded as open or remedied against a specific number, which is free and genuinely worth running. What no decode does is prove that a previous owner ever presented the vehicle. A campaign showing as remedied means a remedy was recorded. A campaign showing as open means the work is outstanding as far as the system knows. And on a vehicle finished by a second company, a campaign against the body may not appear against the chassis number at all.

Condition, and the specification as it stands today. A decode reads the certified build. It does not read the rebuilt engine, the swapped differential, the re-cored radiator, the replaced fifth wheel or the body that was moved onto a different chassis. Original specification and current specification are two separate claims, and only the first has any chance of appearing in a record. Read the fields, then go and verify the metal.

Damage that never reached a record. Collision history enters the file only where an insurer or a state filed something — a total-loss report, a title brand. A repair paid for privately leaves no trace at all. Our page on accident checks by VIN sets out which events reach the record and which never do.

Reading the number off the vehicle

Whatever the listing says, the number to work from is the one on the vehicle, read with your own eyes rather than copied out of an advert, and read from more than one place.

Before you do anything else with a number that arrived by text message or was read off a photograph of a screen, run the check digit. Position nine is computed from the other sixteen characters, so a mistyped number usually fails arithmetically before it has cost anyone a journey. Our validator page explains how to run that check by hand.

Two readings that disagree with each other is a finding rather than a transcription problem to shrug off, and so is a label that looks newer than the aperture around it, or fixings that have obviously been disturbed. Where the numbers on a vehicle do not agree with each other or with the paperwork, our page on VINs that do not match covers what that means and what to do about it. On a bodied truck, remember that a second plate from the finishing company is expected, and that a number belonging to the body is not a contradiction of the chassis number.

The records that sit around the number

The decode is the cheap part and the fast part. The record is where used-vehicle money is won and lost, and the record is retrieved rather than decoded — it lives in title files, insurer reports and recall databases, keyed to the number rather than encoded inside it.

Three retrievals do most of the work, in this order. The federal recall lookup is free, per-vehicle and authoritative on open campaigns against that number. The theft check is also free and answers a question that ends a purchase outright; how to check if a vehicle is stolen covers running it. And the title history — the brands, the state-by-state chain, the odometer readings recorded at each titling — is the one worth paying for. Our title-check page explains what comes back and, just as usefully, what structurally cannot.

Know the boundaries of the free tools before leaning on them. Our page on what a free VIN check actually returns sets out what each one covers, because a clear result from a database that only includes participating members is a weaker statement than it looks. Free checks start the enquiry. They do not finish it.

Where a vehicle carries a brand on its title, the brand is the purchase. What a branded title means ranks the brands by how much each should worry a buyer. And when all of that is done, book a pre-purchase inspection, because the condition of one specific vehicle is the thing this entire page has been telling you the number cannot carry.

Common questions

Is there an official Kenworth VIN decoder?

Not a separate one, and none is needed. These vehicles carry the same seventeen-character number as everything else certified for this market, and NHTSA’s vPIC register resolves the manufacturer prefix for every make on the same terms. A general decoder handles the make.

What are the Kenworth WMI codes?

The register lists 11. Filed as Truck: 1XK, 2XK, 3WK, SFN, 3WM, 3XK and 3NM. Filed as Incomplete Vehicle: 1NK, 2NK, 3BK and 3NK. They are held between 2 registered company names, KENWORTH TRUCK COMPANY and KENWORTH MEXICANA SA DE CV.

My decode returned a country I was not expecting. Is it wrong?

Probably not. Only 2 of the 11 codes are recorded against the United States. Mexico carries 5, Canada 2 and the United Kingdom 1, and one code carries nothing at all. The country column records where the registering entity filed, not where a vehicle was assembled, so an unfamiliar country in a result is the filing showing through rather than an error.

Why does one of the codes have no country?

Because the field is blank in the register. 3NM is filed under KENWORTH MEXICANA SA DE CV as a Truck and records no country. That is ordinary — 13 of the 36 makes in our read have at least one code with an empty country field. It is the only blank one here; the other 10 codes all carry a country, and the make’s country list names 4 rather than 11 because it lists the distinct countries those codes name rather than one entry per code. We do not guess at what the blank ought to say.

What does Incomplete Vehicle mean on a decode?

It means the code covers a vehicle that left the factory without its final body, for another company to finish. 4 of the 11 codes are filed that way. The decode answers for the chassis and cab. The equipment behind the cab was built and certified by a different company, which has its own name, its own plate on the vehicle and its own recall record.

Where do I find the body builder’s details?

On the vehicle rather than in the decode. The company that finished the build applies its own certification label when it certifies its stage of the work. Start at the driver’s door aperture, then look in the cab, in lockers and on the frame, because a finishing company puts its plate where its own build allows.

Do the codes all date from the same year?

No. 7 were registered on one day in May 2015, 2 in March 2017 and 2 in October 2018. Those dates record when each code was entered in the register. They say nothing about when any vehicle was built or sold. The date that belongs to a vehicle is the model year at position ten of its own number.

How many models does the register hold for the make?

44. That is the vocabulary the federal decoder can return for a vehicle whose number resolves to this manufacturer, across all years, rather than a current line-up. The archived read behind this page carries the count and not the list of names, so no model names are printed here.

Will a decode tell me the engine, axles or sleeper configuration?

Where the manufacturer submitted those fields, a decode of a real number can return some of them, and the engine manufacturer field is one worth reading where it is present. But it describes the certified build. An engine or driveline since rebuilt or replaced leaves no trace in the number, so read the field and then verify the vehicle.

Can a VIN check show whether a recall was completed?

It shows whether a campaign is recorded as open or remedied against that number, which is free and worth running. It does not prove that anybody presented the vehicle, and on a truck finished by a second company a campaign against the body may sit under a separate record entirely. Read the campaign text rather than only the flag.

Are there false matches when I search the register for the name?

No. Querying the register for this name returns 0 unrelated results, so the 11 codes listed above are the whole set. The make also registers under its own name rather than under a parent group, so there is no second entry to go looking for.